Avtor/Urednik		Kržan, M
Naslov		Razporeditev, značilnosti, pomen in vloga histaminskih H1 in H2 receptorjev v srcu
Tip		monografija
Kraj izdaje		Ljubljana
Založnik		Medicinska fakulteta
Leto izdaje		1995
Obseg		str. 102
Jezik		slo
Abstrakt		This research work describes identification and characterization of cardiac histamine H1 and H2 receptors using molecular pharmacological and functional pharmacological approaches. Using radiolabels the molecular properties of H1 and H2 receptors were identified and characterized in female guinea pig myocardium. Mapping with 3H-mepyramine revealed the existence of high and low affinity binding sites for the ligand with an equilibrium dissociation constant (KD) of 04 +- 9 fmol/mg of protein for the high affinity and a KD of 4.5 +- 0.6 nM and a Bmax of 466 +- 66 fmol/mg of protein for the low affinity binding site. For 3H-tiotidine a single population of binding siters with a KD of 1.0 +- 0.07 nM and a Bmax of 27 +- 2 fmol/mg of protein was found. 3H-mepyramine binding was displaced by competitors in rank order typical for the functional H1 receptor: mepyramine = triprolidine more th. histamine more th. 2-methylhistamine more th. 4-methylhistamine. The rank order of competitor potencies was: famotidine more th cimetidine more th. mepyramine more th. impromidine more th. histamine more th. 4-methylhistamine - typical for the functional H2 receptor. To establish the validity binding studies, there should exist a quantitative correlation between affinities obtained in binding andfunctional studies. In functional stuides the positive inotropic and chronotropic responses induced by histamine, H2 specific agonists impromidine and 4-methylhistamine, and H1 specific agonist 2-methylhistamine were observed. The results confirmed that histamine H1 receptors mediate the positive inotropic effect in quinea pig left atria, whereas in guinea pig right atria the stimulation of histamine H2 receptors leads to positive inotropic and chronotropic effects. The comparison of binding and functional parameters of histamine H1 receptors revealed no good correlation.(trunc.)
Deskriptorji		MYOCARDIUM RECEPTORS, HISTAMINE H1 RECEPTORS, HISTAMINE H2 GUINEA PIGS ANIMALS, LABORATORY RADIOLIGAND ASSAY PYRILAMINE MYOCARDIAL CONTRACTION HISTAMINE METHYLHISTAMINES IMPROMIDINE